The bone-metal interface is very important to many types of materials in vitro, especially those which are used to reinforce the structure of the body.  Synthetic structural components are usually metals that are biocompatible. 

Specifically, the bone-metal interface is comprised of any point at which the material meets the bone.  The chemistry and mechanics of the interface of the bone tissue and the material can cause horrific effects.  Splitting in the bone by a strong longitudinal force is a common problem that leads to surgery to fix the problem.  Both the longitudinal force and a shear force can cause problems in the interface by cracking cementing agents or actually cracking the bone itself. 

Complications in more complex methods of structural reinforcements has led to the idea of simplicity and a more ideal material for the situation.  For example, cementing agents in hip-prosthetics causing Osteolysis, has led to the belief that an implant with no cementing agent would be preferable.